Want to know how many people are currently living in Britain? Well, just put your finger up to the wind and pick a number. Any number.

By Melanie Phillips

Because that’s pretty well as near as dammit the way the Government has been estimating the number of immigrants coming to the UK.

A report by the Public Administration Select Committee has said that migration figures used by ministers could not be trusted, and described the key measurement of migration as ‘little better than a best guess’.

Migration estimates, it said, were based on random interviews of around 800,000 people passing through ports and airports, of whom only about 5,000 were actually immigrants.

Clearly this research, which was designed merely to monitor tourist trends, could not possibly provide an accurate measure of migration.

Nevertheless, the Government had used this sample to boast of its progress towards cutting net migration from 252,000 in 2010 to 100,000 per year by 2015. In other words, the Government’s own figures are totally worthless.

So what does the Home Office say to this devastating conclusion? Why, that ‘Government reforms on immigration are working and the statistics do show that net migration is at its lowest level for a decade’.

But the whole point of the MPs’ report is that they cannot possibly show any such thing. So the Home Office response is surely as worthless as are its statistics.

Moreover, the implications go way beyond estimating whether immigration numbers are merely up or down.

For it is upon such research into population movements that any government must base its administration of the country.

How else can it possibly estimate the likely demand for houses, schools, hospitals and other public services unless it knows how many people will need those services?

Without such basic information, government turns into a shambles.

Yet this is precisely what has happened. Is it any wonder that our public services are tottering towards collapse?

This statistical farce represents a double fraud upon the public. First, although ministers pretended they were getting on top of the immigration problem, they had allowed it to get on top of them.

Second, the reason they didn’t ask the right questions to find out what the immigration figures really were is almost certainly that they didn’t want to know the answer.

To grasp the true — and truly wicked — dimensions of this deception, we need to cast our minds back to the Labour administration under Tony Blair and Gordon Brown. This set out to change the very identity of Britain — and to do so, furthermore, by stealth.

In 2009 Andrew Neather, a former speech writer for Labour ministers, revealed that the real purpose of Labour’s immigration policy had been to transform Britain into a new kind of society altogether, where British attributes would have no greater status than any other culture.

Labour imagined that, by creating such a multi-racial, multicultural society, it could eradicate prejudice from the human heart.

It also just happened to be a way of gerrymandering the vote, by creating a great pool of Labour voters from immigrants who would overwhelmingly vote that way.

Yet Labour concealed the truth about what it was really up to because it rightly believed that its own core voters — the indigenous British working class — would rise up in revolt.

Undoubtedly, a measure of immigration is very good for the country. But if the numbers are too high, the infrastructure just cannot cope and priorities become distorted. This is precisely what has been happening.

Last week it emerged that, between 2001 and 2011, almost 500,000 immigrants were given social housing at a cost to the taxpayer of up to £8 billion. And this when a record 1.8 million British families are on the social housing waiting list.

When they came to power, David Cameron’s Tories decided to treat the issue of immigration as taboo, in order to shake off Theresa May’s notorious depiction of the Conservatives as ‘the nasty party’.

They were forced to ditch this approach under the impact of the work done by the pressure group Migration Watch, which exposed the unsustainable reality of the true immigration figures, and volcanic public hostility to continued mass immigration, expressed through the rise of UKIP.

In the face of these twin pressures, ministers claimed to be bringing the immigration total down, while shielding their eyes from what it actually was.

This is because to address the problem properly would mean confronting its root causes — such as the UK’s membership of the EU, whose foundational principle is to allow the free flow of migrants on the basis that the only borders it recognises are those of the European superstate itself.

That’s why the current restrictions on Romanian and Bulgarian immigration will be lifted at the beginning of next year.

It remains anyone’s guess how many of those 29 million who will then be entitled to come to the UK will actually do so.

But clearly the potential for tipping into outright calamity what is an already socially disruptive situation — with illegal Romanian shanty encampments even in the middle of London’s Mayfair, for heaven’s sake — is very high.

Ministers would also have to deal properly with the human rights culture, whose interpretation by English judges in handing out benefits to immigrants and refusing to allow them to be deported has made a mockery of the dues of citizenship.åç

Now, the Government knows perfectly well that for all its tough noises on delivering a referendum on the EU or reforming human rights law, it has, in fact, no intention of de-coupling the UK from either of them. Yet it is facing a huge challenge from UKIP on both immigration and EU membership.

So it has come up with idiotic and distasteful gimmicks, like the Home Office van driven around six London boroughs bearing billboards declaring: ‘In the UK illegally? Go home or face arrest.’

Since the number of illegal immigrants it has persuaded to do just that is likely to be vanishingly small, this combined extreme fatuity with unpleasantness — so much so that it even outdid UKIP, whose leader Nigel Farage denounced it as ‘nasty and with elements of Big Brother’.

The deeper reason for this whole farce is that for decades now, immigration has been the untouchable subject.

Fear of being labelled ‘racist’ has paralysed the entire political class — leaving the way clear for Labour ideologues to use mass immigration to remake British identity, all but collapsing public services under the weight of numbers and driving down wages to undercut British workers.

None of this has dared be said by a mainstream politician for fear of vilification. Anyone who has the audacity to uphold the rule of law over illegal immigration, the duties of citizenship over global freeloading and the legitimacy of safeguarding Britain’s historic identity by expecting immigrants to assimilate into that identity rather than create a new one altogether, is denounced as a bigot.

Thus the progressive wreckage of a country has been enabled and sanctified. And now we can see that, whereas Labour concealed what it was doing to dupe its core vote, the Tories have concealed what they are not doing in order to dupe their core vote.

What was that double bang in the distance? Why, shares in the Home Secretary, Mrs May, dropping like a stone — and the UKIP rocket taking off again with a fresh injection of fuel.